Effect of temperature rise on characteristics of a standing wave ultrasonic motor

Heat loss occurs in the process of energy conversion, which causes the temperature rise and performance degradation of ultrasonic motor. In this article, a novel theoretical model is developed to investigate the temperature field and output characteristics of a standing wave ultrasonic motor. The roughness of contact surface and the interaction between temperature rise and material parameters of stator are taken into account in the proposed model. The frequency–temperature characteristics of stator are studied, and the changes in the dielectric coefficients of piezoelectric materials with respect to the temperature are determined by experimental data. The accuracy and effectiveness of the developed model are validated by correlative experiment. The results show that the developed model can not only predict the temperature variation of motor in continuous operation but also evaluate the influence of surface roughness and various input parameters on output characteristics of motor. These researches will give useful guidelines for optimizing heat source and enhancing reliability of motor.